The invention relates to an energy absorber and hinged deflection plate for deflecting engine debris fragments from their potentially dangerous tangential trajectory from a core of a gas turbine engine to an aft direction to avoid uncontrolled impact with adjacent portions of the aircraft and surrounding environment.
The operation of a gas turbine engine involves the possibility of catastrophic failure of rotating components such as turbine hubs, turbine blades, portions of the rotating shaft as well forward fan blade fragments or compressor components. Since the velocities of revolution of turbines and other components in a gas turbine engine are relatively high, centrifugal forces acting on rotating components must be dealt with in the design of safety features for the engine.
Turbine rotor cracks, breaks or other malfunctions of the turbine can eventually result in disintegration if undetected and uncorrected. The high centrifugal force causes turbine debris to be expelled tangentially outwardly at a high velocity with substantial kinetic energy. To prevent catastrophic damage to surrounding airframe components, passenger cabins or instruments, containment rings or shrouds are generally provided radially outward of the turbines and other rotary components to impede the debris trajectory, absorb kinetic energy or deflect debris to prevent such damage.
For example, in International Publication WO 92/07180 a radial turbine containment system includes primary and secondary containment rings with a deflection ring to cooperatively interact and retain debris fragments within the plane of rotation of a turbine wheel.
Another example of retaining or deflecting of fan blade fragments is shown in U.S. Pat. No. 6,206,631 to Schilling. The fan casing surrounding the fan blades includes a deformable cantilevered inner shell with various types of frictional dampening devices to absorb the impact and deflect broken blade fragments.
It is an object of the present invention to absorb the energy and deflect rotating component debris fragments such as turbine blades and rotor fragments from their potentially dangerous tangential trajectory from the core of a gas turbine engine, preferably to a direction so as to exit along a path that will result in no hazardous secondary damage.
It is a further object of the invention to avoid the disadvantage of the prior art by containing and deflecting debris fragments through a bypass duct on a turbofan engine or within the exterior cowling of a turboprop or turboshaft engine rather than retaining such debris within the combustor or other adjacent engine core components.
Further objects of the invention will be apparent from review of the disclosure, drawings and description of the invention below.
The invention provides an energy absorber and deflection device for deflecting engine debris fragments from their tangential trajectory from a core of a gas turbine engine. The device includes a deflection plate radially spaced from a protected portion of the periphery of the rotor, adapted to cover the protected portion in a closed position, and to swing open about a fore edge of the deflection plate to a deployed position. A flexible joint secures the fore edge of the deflection plate to the engine and a frangible joint secures an aft edge of the deflection plate to the engine. In the case of a turbofan engine, the deflector plate may form part of the inner bypass duct surface to deflect debris to exit aft through the bypass duct, and in turboshaft and turboprop engines the deflector plate serves to deflect debris and reduce debris velocity to contain debris within the engine cowling or nacelle.